There is one Pokemon phenomenon that isn't proving popular and doesn't seem to be catching on.

An email-based computer virus, that plays on the popularity of Pokemon, has been found infecting machines in the US.

Anti-virus companies say it is the first virus aimed at children and it tries to exploit the fact that they tend to be less careful about security than their parents.

Experts say that so far the virus has done little damage.

Like many other malicious programs, the Pokemon virus travels in an email message with the subject line: "Pikachu Pokemon".

The message itself reads: "Great Friend! Pikachu from Pokemon Theme have some friendly words to say. Visit Pikachu at http://www.pikachu.com. See you."

Bouncing Pikachu

Travelling with the message is an attachment that, when clicked, launches animation of a bouncing Pikachu - the yellow mouse-like Pokemon that fights with electricity.

But at the same time that the Pikachu is bouncing around the screen the program is also making changes to a key configuration file on the PC.

The change means that the next time the machine is switched on all the files in the Windows and Windows/System directories are destroyed.

The virus seems to have done little damage because users get a warning when it tries to delete important files and asks them to approve the action.

If a person contracting the virus uses the popular Microsoft Outlook program the program attempts to email itself to every person it finds in the address book.

In May this year the ILOVEYOU virus wrought havoc around the world by travelling this way.

Graham Cluley, senior technology consultant at anti-virus company Sophos, said the virus had been known about since the end of June and anyone with up to date anti-virus software was unlikely to be infected by it.

So far the virus only seems to be doing damage in the US. Sophos said it had been detected in Europe and Japan but no-one seems to have been caught out by it.

"The virus author is deliberately targeting children and parents in an attempt to spread his virus further," said Mr Cluley.

"What we are seeing here is another example of virus writers using psychology as well as technology.